clib2 Code

- The general test program now also exercises the time conversion functions.

- mktime() is supposed to convert the time specification, given as local
time, into the number of seconds since January 1st, 1970, relative to
UTC. This didn't really work up until now since the time value returned
was given as local time.

- Moved the common DateStamp to time_t conversion code into a shared
function.

- The fall-back function for converting time into a string in strftime()
now calls itself for the "%x" and "%X" format specifiers.

- Added instructions for switching over an existing Amiga 68k GCC installation
to use "clib2".

- Added a check against DBL_EPSILON in log() and log10() in place of the
check against 0 that used to be in there.

- The default console output window opened when a program is launched
from Workbench would open and stay open. This was not intended to
happen and is a side-effect of the new stdio initialization code which
checks if the stdio streams are in non-blocking mode. Fixed.

This commit was manufactured by cvs2svn to create tag 'V1_186'.

- Added a missing definition to stdio_init_exit.c which is part of
the OS4 header files, but not of the older header file distributions.

- close() did not reset the non-blocking file property, as it should
have. This only worked for files which were closed anyway, but not
for the stdio streams. Fixed.

- Lost some more code that is not required for AmigaOS 4.x and can be
handled conveniently through conditional compilation.